On Sun, Oct 11, 2026 at 01:53:56PM +0100, Gavin Smith wrote:
> On Wed, Oct 07, 2026 at 07:00:33PM +0100, Gavin Smith wrote:
> > The obvious way to fix this would be change "@nabla" to "\nabla" in
> > the source file:
> >
> > @section Laplacian (@math{\nabla ^2}) operators
> >
> > Unfortunately, this does not work: \nabla prints as "\nabla", not as the
> > upside-down triangle symbol. This is presumably what led to using @nabla
> > in the section title in the first place.
> >
> > Even if we could make this work in texinfo.tex (maybe using the
> > \scantokens extension of e-Tex), it would not be an immediate fix for the
> > current problem, as it wouldn't work with old versions of texinfo.tex,
> > so authors would not have a good reason to change their Texinfo files.
> > But it would avoid this problem in the first place.
>
> I've now done this in texinfo.tex (version 2026-10-10.09), using
> \scantokens, so the @section line above outputs as you expect, with the
> "\nabla" sequence correctly printing as ∇.
>
> I will probably upload the latest texinfo.tex to ftp.gnu.org in a few
> days unless somebody reports further broken behaviour.
For interest, this issue was reported in 2003 by Patrick Guio:
https://lists.gnu.org/archive/html/help-texinfo/2003-01/msg00021.html
Karl suggested the macro workaround in this mail:
https://lists.gnu.org/archive/html/help-texinfo/2003-01/msg00027.html
